This invention relates to a method of producing L-glutamic acid by fermentation.
In order to obtain the best yield of L-glutamic acid in known fermentation proceses, the amount of L-biotin in the fermentation medium should be controlled in a very narrow range. However, beet or cane molasses, which are available as the carbon sources in a reasonable price, contain very high amount of biotin, and then the fermentation medium composed with such molasses inevitably contain excessive amount of biotin. In order to avoid the undesirable affection of excessive amount of biotin on L-glutamic acid production, surfactants, or antibiotics are added to the fermentation medium when excessive amount of biotin is contained in the known method.